Yarn tension and trap for use in self-threading weaving shuttles



Jan. 17, 1956 w, J. GOSSELIN 2,731,043

YARN TENSION AND TRAP FOR USE IN SELF-THREADING WEAVING SHUTTLES Filed July 51, 1952 United States Patent YARN TENSION AND TRAP FOR USE IN SELF- THREADING WEAVIN G SHUTTLES Wilfrid J. Gosselin, Methuen, Mass., assignor to U S Bobbin & Shuttle Company, Lawrence, Mass, a corporation of Rhode Island Application July 31, 1952, Serial No. 301,846

3 Claims. (Cl. 133-217) This invention pertains to weaving shuttles of the selfthreading type such as are used in weft-replenishing looms and relates more especially to a combined tension and yarn trap for use in such a shuttle.

Shuttles of the above type have a bobbin chamber and a passage, usually formed in a so-called threading block, leads forwardly from the bobbin chamber and then laterally to the yarn delivery eye. customarily, a yarn tension unit is arranged within a chamber in the thread ing block, commonly near the rear end of the latter, the tension unit comprising opposed elements designed to engage the yarn and frictionally resist its movement as it is drawn from the bobbin. Since the shuttle is of selfthreading type, the tensioning unit must allow the yarn automatically to assume operative relation to the tensionapplying elements during the first pick after replenishment. This necessarily means that the tension unit must be of a design such that the yarn which, during the first pick after replenishment, extends in a substantially straight line forwardly from the end of the bobbin may easily find its way into operative relation to the tensionapplying elements. On the other hand, this requirement for easy and automatic entry of the yarn, involves the further problem of keeping the running yarn, which balloons from the end of the bobbin, from escaping from between the tensioning elements and thus becoming unthreaded from the shuttle. This is particularly true when dealing with yarns of the synthetic type, some of which are very wiry and slippery. Such a yarn may act very much like a coiled spring as it leaves the bobbin, and has a strong tendency to escape from between the tensioning elements. One of the most common types of tension unit comprises a pair of rigid friction pads of stiff sheet metal having opposed, smooth yarn-contacting faces between which the yarn passes in frictional engagements with said faces, the pads being urged toward each other by springs and being shaped at their upper ends to provide a downwardly convergent inlet throat through which the yarn enters between the yarn-contacting faces of the pads. This provides easy entry of the yarn, but likewise an easy escape, and for this reason various types of yarn trap have been proposed for use with tensions of this sort. However most such traps heretofore proposed have proven to be unsatisfactory for one reason or another; for instance some such traps interfere with the easy entry of yarn between the tension pads; others are too complicated and expensive for commercial use; others have a tendency to cause yarn breakage, and others are not reliably effective or useful with yarns which are slippery or wiry. The present invention has for its principal ob ject the provision of a combined yarn tension and trap which is easily threaded, but which effectively prevents accidental escape of yarn even though the yarn be wiry and slippery. A further object is to provide a combined yarn tension and trap of very simple and inexpensive type and which is applicable,'as a substitute for usual tension. A further object is to provide a combined yarn tension and trap which is readily adaptable to use with ice bobbins of either right or left-hand wind. A further object is to provide a combined yarn tension and trap which may be arranged either at the extreme rear end of the threading block or at an intermediate point in the yarn passage, or at both places if desired. Other and further objects and advantages of the invention will be pointed out in the following more detailed description and by ref erence to the accompanying drawings wherein:

Fig. l is a fragmentary diagrammatic plan view of a shuttle of the self-threading type, showing the threading block provided with a tension unit according to the present invention, certain elements of this tension unit being exaggerated in size for clearness in illustration;

Fig. 2 is a fragmentary rear view (to larger scale than Fig. l) of the threading block removed from the shuttle;

Fig. 3 is a rear elevation (to larger scale than Fig. 2) showing the tension pads removed from the threading block;

Fig. 4 is a plan view of a blank (to smaller scale than Fig. 3) from which one of the tension pads, in accord ance with the present invention, is made;

Fig. 5 is an elevation of the right-hand tension pad of Fig. 3 (to smaller scale than Fig. 3) and viewed from the right-hand side of Fig. 3;

Fig. 6 is a rear edge elevation of the pad shown in Fig. 5;

Fig. 7 is a section substantially on the line 7-7 of Fig. 5;

Fig. 8 is a diagrammatic plan view of a threading block, removed from the shuttle, illustrating an arrangement in which two of the tension units of the present invention are mounted in the same threading block, the trapping fingers being exaggerated in size;

Fig. 9 is a section (to much larger scale than Fig. 8)- on the line 9-9 of Fig. 8, looking rearwardly of the threading block and showing a tensioning unit, according to the present invention, arranged with its yarn-trapping finger directed forwardly; and

Fig. 10 is a front edge elevation of the tensioning pads of Fig. 9 showing them removed from the threading block.

Referring to the drawings, the numeral 1 designates a shuttle of generally conventional type such as is used in a weft-replenishing loom. This shuttle has the bobbin chamber 2 within which the bobbin 3 is arranged, and a yarn passage 4 leading forwardly from the bobbin chamber, a portion 4 of this passage being defined by the walls of a threading block 5, usually of metal, which is set into a cavity in the forward end of the shuttle. The yarn passage has a laterally directed portion which terminates at the yarn-delivery eye 6. In the rear end portion of the threading block 5 there is provided a chamber 7 for the reception of the yarn tensioning unit or units.

As illustrated more particularly in Fig. 3, the yarn tensioning unit 8 comprises two vertically elongate pads 9 and 10, whose opposed or inner surfaces make frictional contact with the yarn Y when the latter is disposed in its normal path extending from the chamber 2 to the delivery eye 6. These pads 9 and 10 are of stiff, rigid material, for example sheet steel, and are provided at their upper ends with suspension elements 11 and 12 which are received in horizontal bores 13 and 14 (Fig. 9) in the oppocurved surfaces, that is to say from the point at which they are tangent to the inner yarn-engaging faces of the pads, the latter are substantially straight and parallel down to the lower ends of the pads which are located near the bottom of the threading block 5. Springs 19 and 20 (Figs. 2 and 9) bear against the outer faces of the pads 17 and 18 respectively, so as to urge the yarn-contacting faces of the pads toward each other, thus to provide frictional contact with the yarn. The outer ends of these springs rest in cups in adjusting screws 21 having threaded engagement with horizontal bores in the legs 15 and 16 of the threading block, these springs being arranged to exert pressure against the pads substantially in the horizontal plane of the normal path of. the yarn Y on its way from the bobbin chamber 2 to the delivery eye 6. The pads as thus far describedmay be substantially like the yarntensionin-g pads of conventional types of yarn tension.

In accordance with the present invention one at least of the pads, for example', the pad 10, is provided with a yarn trapping finger F. Preferably, in making this pad 10 there is first provided a blank 10 (Fig. 4) of appropriate material, for example sheet steel, having oppositely directed, horizontaltabs 12 at its upper end which are curled to form the suspension element 12, the upper portion of the blank then being bent to provide the curved surface 18. The blank 10 has the projecting, diagonally downwardly integral tongue F and is provided with a hole H near its lower end for the reception of a positioning pin R, the pad 9 having a similar hole and the pin R passing loosely-through both. pads so as to steady them and keep them in vertical alignment. The longitudinal edges of the blank 10 are then bent to form stiffening flanges 23 and 24 (Figs. 5 and 7) and the tongue F is twisted out of the plane of the blank as shown in Fig. 6 to provide the substantially straight trapping finger F. When the pad 10, thus formed, is assembled with the pad 9', the finger F extends diagonally downv from its integral union with the pad 10, across the space between opposed faces of the pads which receives the yarn Y and terminates at apoint intermediate the width of the rear flange of the opposite pad 9. As illustrated (Figs. 3, 9 and 10) the integral union of the finger F with the paid 10 is at a point well above the normal. path of the yarn Y, and preferably the free end of the finger is also above the hori zontal plane of this normal yarn path.

When the shuttle is being replenished with yarn, the first pick of the shuttle draws the yarn down into the throat T and the tension occasioned by the rapid movement of the shuttle is sufficient to cause the yarn to move down through the throat T and to slide down the smooth straight upper surface of the finger F and to snap beneath the free end of tl'ie'yam-trapping finger F so that the yarn takes a position beneath thisfinger; On the next and following picks ofv the'shuttle, although the yarn may be wiry and smooth andmay' tend to balloon very freely from the end of the bobbin 3, nevertheless it is impossible for this yarn to find its way back above the trapping finger F.

While, .as illustrated in Fig. 3, the yarn trapping finger F is at the rear edge of the pad 10, it is contemplated that the trapping finger may be arranged at the forward edge of the pad as illustrated, for example, in Fig. 9, which is aview looking'toward the forward edges of the pads 9 and 10. This'arrangeme'nt' may be preferred to that shown in- Fig 3' because of the fact that the yarn trappingfinger F is then within the'th-re'ading block so that it is not exposed to mechanical injury. It is further contemplated that both arrangements may be employed in the same shuttle as illustrated in Fig. 8', where one tensioning. unit 8' is shown as arranged near the rear end of the threading block 5- with its finger F arranged (as in Fig. 3r.) whilc'a second tensioning unit 8 is arranged in theforward' part of the tension chamber 7* with its finger F arranged as'shown in Figs; 9' and L0.

The combined tenstonand 'trap according to the pres- 4 ent invention is of the simplest construction, very easy to make and easy to install. It may be installed in threading blocks of a usual type without requiring any particular change therein, except when two tensioning units are to be used as shown in Fig. 8 in which event the tension chamber 7 in the block would be enlarged forwardly.

It should further be noted that this combined tension and yarn trap comprises but two essential elements, that is to say the pads 9 and 10, with no separate and independent elements other than the springs customarily employed. The yarn trapping finger is an integral element of one of the pads and is in a position to cooperate with a yarn which has been moved down into its normal path, leading from the bobbin chamber to the yarn delivery eye, and that this finger does not function until the yarn has moved down into operative relation to the tension applying pads. The yarn trapping finger F extends downwardly at a steep angle, so that the yarn may easily follow it down without requiring great tension to draw it beneath the free end of the finger, the free end of the finger, of course, being spaced slightly from the flange of the opposite pad 9 so that the yarn may pass between them.

Obviously, the trapping finger may be carried by either of the pads of a pair, according to Whether the yarn is wound right or left-hand on the bobbin, likewise, an arrangement such as suggested in Fig. 8, makes possible a trap for either Wind, without modification, if desired, in fact, a trapping finger may be carried by both pads of the same tension unit, if so relatively arranged that they do not prevent yarn entry.

While it has been suggested that the pads be of sheet metal it is to be understood that they may be of any other material found suitable for the purpose, such, for example, as one of the synthetic resins, some of the latter having. been found highly resistant to the cutting action of rapidly moving yarn. It is further to be understood that while a threading block 5 has herein been indicated merely by way of illustration, the invention is not concerned with the particular shape or formation of the threading block itself but only with the tensioning and trapping of the yarn as the latter enters the yarn passage. It is further to be understood that the exact location of the tensioning and trapping units rearwardly or forwardly of the threading block is unimportant so long as the tensioning unit is so located that the yarn will be received with certainty by the tensioning unit during the first pick after replenishment. A desirable embodiment of the invention has herein been illustrated and described but it is to be understood that the invention is not necessarily limited to the precise details here shown but is broadly inclusive of any and all modifications falling within the scope of the appended claims.

I claim:

1. A threading block for use in a weaving shuttle of the automatic threading type, said block having a forwardly extendingyarn passage through which the yarn normally passes to a lateral yarn-delivery eye, the block having a tensioning chamber and a pair of tensioning units located in said chamber one ahead of the other, each unit comprising a pair of independent vertically elongate tension pads of stilf material having opposed yarncontacting faces, spring means urging the pads of each pair toward each other thereby frictionally to contact yarn moving along the normal path which it follows during the second and later picks of the shuttle after replenishment from the rear end of the block to the delivery eye, one pad of each pair having a yarn trapping finger integrally joined to its edge at a point above the level of said normal yarn path, each finger having an upper surface which slopes too steeply to support the yarn during the first pick of the shuttle after replenishment, each finger extending diagonally down and transversely across the space between the yarn-contacting faces of the pads, and terminating adjacent to but spaced from the edge of the opposed pad of the respective pair, one of said fingers 5 being at the forward edge of its respective pad, and the other of said fingers being at the rear edge of its respective pad.

2. In a self-threading weaving shuttle of the kind wherein a yarn passage leads forwardly from a bobbin chamber in which a bobbin is positioned, the passage terminating at a lateral yarn-delivery eye and wherein a yarn tensioning unit is located within said yarn passage adjacent to the bobbin chamber, means located at the rear of the tensioning unit operative to trap yarn drawn from a bobbin on which the yarn is wound in one direction, and means located forwardly of the tensioning unit operative to trap yarn drawn from a bobbin on which the yarn is found in the opposite direction.

3. In a self-threading weaving shuttle of the kind wherein a yarn passage leads forwardly from a bobbin chamber in which a bobbin is positioned, the passage terminating at a lateral yarn-delivery eye and wherein tensioning means is located within said yarn passage, said tensioning means comprising two pairs of tensioning pads, one pair being spaced forwardly of the other, in the direetion of yarn travel, each pair of pads having opposed vertically elongate substantially straight yarn-contacting faces between which the yarn passes when following its normal path from the bobbin chamber to the yarn-delivery eye, one of the pads of each pair having integrally joined thereto a downwardly inclined yarn trapping finger, each finger extending across the space between the opposed pads to overlap the edge of the other pad, one of said fingers being joined to the right-hand pad of one pair and the other being joined to the left-hand pad of the other pair, thereby to trap yarn unwinding from the bobbin, whether the yarn be wound right-hand or lefthand upon the bobbin.

References Cited in the file of this patent UNITED STATES PATENTS 749,353 Baldwin Jan. 12, 1904 1,720,411 Davis July 9, 1929 2,087,871 Brown July 20, 1937 2,107,917 Tebo Feb. 8, 1938 2,125,405 Tebo Aug. 2, 1938 2,152,223 Tebo Mar. 28, 1939 2,170,541 Tebo Aug. 22, 1939 

